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This case report describes the treatment of a patient with unerupted maxillary right central incisor, lateral incisor, and canine in a Class III malocclusion with asymmetry of the lower face. Sequential traction of the 3 unerupted teeth with a light force system was used in the treatment. The results remained stable during the 4-year retention period.
This clinical report describes a combination treatment approach to an esthetic defect that resulted from diastemata and peg-shaped lateral incisors. Minor tooth movement was achieved through the use of a removable orthodontic appliance and orthodontic rubber band, and full-coverage PFM crowns were placed on the lateral incisors. These complementary orthodontic and restorative procedures successfully corrected the defect.
OBJECTIVE: The vasculature within the socket is reportedly involved in determining the position of continuously erupting teeth. Thus, loss of body fluid in anesthetized rats, which would affect the vascular physiology, should influence tooth movement. We investigated the effects of an infusion of Ringer's solution on the systemic arterial blood pressure, regional blood flow at the base of the incisor, and axial tooth movement in anesthetized rats to determine the cause of tooth displacement. MATERIAL AND METHODS: In the experimental group, the animals received intravenous infusions of Ringer's solution at 27 microl/min for 13 h. In the control group, the animals did not receive the infusion. RESULTS: The infusion of Ringer's solution suppressed an increase of the mean arterial blood pressure from 86 to 80 mmHg and a decrease of the regional blood flow from 170 to 217 mV, and increased the eruption rate from 267 to 361 microm/13 h during the experimental period. There was a positive correlation between the eruption rate and regional blood flow, and a negative correlation between the blood pressure and regional blood flow. CONCLUSIONS: These results suggest that an infusion of Ringer's solution can cause an increase in the regional blood flow, resulting in increased fluid volume, elevated intra-socket pressure, and increased eruptive movement. It is possible that the regional vascular volume and/or pressure within the socket play an important role in determining the position of the incisor.
OBJECTIVE: The aim of this study was to compare the fracture resistance of endodontically treated maxillary central incisors with incomplete crown ferrules after chewing simulation. MATERIAL AND METHODS: Forty caries-free maxillary central incisors were divided into 4 groups (n = 10). Endodontic treatment was performed. Teeth were decoronated 2 mm above the cemento-enamel junction (CEJ). Group I (control) provided a 360 degrees circumferential 2-mm ferrule. In group II, a 2-mm ferrule was present on the palatal aspect (status after occlusal overload), and in group III on the facial aspect (status after traumatic injury). In group IV, the ferrule was interrupted by bi-proximal cavitations (simulating caries treatment). The teeth received glass fiber reinforced posts and composite core restorations. All-ceramic crowns were adhesively cemented. Specimens were simultaneously exposed to thermal cycling and mechanical loading (1.2 million cycles; 6,000 cycles 5 degrees/55 degrees C) and finally statically loaded until failure in a universal testing machine (crosshead speed = 1 mm/min). For statistical analysis, the Kruskal-Wallis test was applied followed by the Mann-Whitney U-test as post hoc testing. RESULTS: The median fracture load values (min./max.) were: group I = 502 (326/561), group II = 658 (280/827), group III = 899 (396/1176), and group IV = 360 (279/646). Analysis revealed statistically significant differences between test groups, except between groups I and IV and groups II and IV. CONCLUSIONS: The fracture resistance of endodontically and post/core restored teeth is dependent on the degree of tooth conservation. An incomplete crown ferrule is associated with greater variation in load capacity and, despite high fracture values, inclines to fracture.
Talon cusp is an uncommon dental anomaly in which an accessory cusp-like structure projects from the cingulum area or cemento-enamel junction of the maxillary or mandibular anterior teeth. This anomalous cusp resembles an eagle's talon. It occurs in both the primary and the permanent dentition. A comprehensive literature review shows that only 37?cases of talon cusps have been reported in the primary dentition, of which only 4?cases report this anomaly on the primary maxillary lateral incisor. Though labial/facial talon cusps have been reported in the permanent dentition, no case of a labial talon has been reported in the primary dentition. We report two females with cleft lip and palate with facial talon cusps on the primary lateral incisor and believe that these are the first cases to be reported. Clinical considerations and debate on the etiology of this anomaly are discussed.
Phosphoprotein was obtained from rat incisor dentin either by extraction at elevated ionic strength after acetic acid demineralization, or by extraction simultaneous with demineralization in neutral EDTA solution. Purification of solubilized proteins was achieved by Sepharose 4B and DEAE-cellulose chromatography. Polyacrylamide gel electrophoresis of the material from the two preparations resulted in one single band. Except for the amino acid analyses, no evidence for a difference between the two phosphoprotein preparations could be found. After additional purification by iso-electric focusing the amino acid analyses demonstrated a similar composition. It is concluded that the two methods for phosphoprotein extraction yield the same product when purified properly. The study did not give any unequivocal answer as to if any phosphoprotein component exists in rat incisor dentin which is covalently linked to the collagen matrix.
OBJECTIVE: The objectives of this study were to observe morphological changes of root canal walls and to evaluate the capability of Er,Cr:YSGG laser for preparation of curved mandibular incisor root canals in vitro. BACKGROUND DATA: There are no published reports on the use of Er,Cr:YSGG laser for curved root canal preparation. METHODS: Twenty curved mandibular incisor root canals (10 and 15 degrees) were prepared sequentially by laser irradiation at 20 Hz, 2 Wusing two different sizes of fine fiber tips (200 and 320 microm in diameters). After laser irradiation, the teeth were bisected longitudinally, and the specimens were observed by stereoscope and scanning electron microscope (SEM). RESULTS: Root canal walls of the irradiated areas showed step-like appearances and openings of dentinal tubules, and root canal preparation, having curvatures of less than 10 degrees, could be carried out by this laser irradiation. CONCLUSIONS: Er,Cr:YSGG laser irradiation is capable of preparing root canals having curvatures of less than 10 degrees.
In orthognathic surgery a three-dimensional positioning of the maxilla is possible by means of the Le Fort I osteotomy and subsequent maxillary movement. In treatment planning and at the time of surgery it is very important to achieve an exact positioning of the upper incisors in relation to the upper lip and the rest of the skull. The Model Positioning Device described here allows three-dimensional positioning of the upper incisors in one- or two-jaw surgery. The reference plane is the upper surface of the upper part of a semi-individually adjustable articulator. The application of the Sandwich Splint enables the three-dimensional positioning of the maxilla in relation to the rest of the skull. The Sandwich Splint ensures that the vertical position of the mandible in relation to the rest of the skull above the osteotomy plane is exactly reproducible in the pre- and post-operative situation in both model surgery and at time of surgery. To this mandibular position the maxilla is positioned in three dimensions, as preplanned. The vertical dimension, which is identically reproducible before and after surgery is measured with a caliper. After surgery the mandible can be rotated into the planned new intercuspidation.
The reaction of previously traumatized teeth to orthodontic force application was investigated. Four groups of children were examined: group T comprised 56 children who encountered trauma to their maxillary incisors; group O comprised 29 orthodontic patients with intact incisors; group TO comprised 28 previously traumatized orthodontic patients; and group C served as the control group (n = 26). Orthodontic treatment was restricted to tipping movement executed only by means of removable appliances. Groups T, O, and TO were followed up longitudinally by means of clinical and radiographic examinations. In most of the cases the reported trauma occurred to teeth with completed roots and affected the crown only. Group TO presented the highest, though relatively moderate, prevalence of root resorption (27.8 per cent) and was followed by groups O and T (6.7 and 7.8 per cent, respectively) while in the control group no resorption was observed. Electrical pulp testing revealed the highest prevalence of loss of tooth vitality in group TO (7.3 per cent) in which the highest prevalence of pulp obliteration was also found. It can be concluded that the combination of trauma with orthodontic tipping renders the teeth more susceptible to complications, especially to root resorption and loss of vitality.
Changes in incisor overbite were compared in 33 subjects who had four second molars extracted and 33 untreated subjects. There was an average increase in overbite of 0.7 mm in the extraction group, significantly different from an average decrease of -0.8 mm in the control group. The tendency to increase in overbite was greater in subjects whose presenting overbite was already reduced. The mechanism responsible for overbite reduction appeared to be a slight distal movement of the dentition, with retroclination of incisors and increase in inter-incisal angle.
The aim of this study was to describe the average and individual patterns of continued eruption of the maxillary incisors and first molars in a longitudinal sample of girls. The sample comprised 14 series of lateral cephalometric films of girls, obtained from the archives of the implant study of Björk (1968). All subjects had bilateral posterior maxillary implants and one or two anterior maxillary implants. Subjects with craniofacial anomalies were excluded. The sample represented various types of malocclusions, but records during periods of orthodontic treatment were excluded from the calculation of average data and average curves. The final sample comprised 147 radiographs in the age range 9-25 years. Data were debugged by comprehensive numerical and graphical procedures. The average cumulative continued eruption from 9-25 years of age was 6 mm downwards and 2.5 mm forwards for the upper incisors, and 8 mm downwards and 3 mm forwards for the upper first molars. This resulted in an average reduction of the occlusal plane inclination (OLs/IPLs) of 4.5 degrees from 9-16 years. Attention is drawn to the fact that due to the continued eruption of the natural teeth, the use of osseointegrated implants with artificial teeth should not be recommended in childhood, adolescence, and early adulthood, unless special provision is made for later revision or replacement of the artificial teeth to compensate for the lack of continued eruption of such implants.
A retrospective study of 26 patients with maxillary incisor root resorption relating to the presence of an ectopic canine was undertaken from case records. The group consisted of nine male and 17 female patients with a mean age of 12.5 years. There was a total of 35 resorbed teeth, 26 lateral and nine central incisors, and these were related to 32 ectopic canines. The resorption tended to be extensive, 30 teeth had pulpal involvement. In two-thirds of cases the pattern of resorption involved both apical and middle thirds of the root. Despite the extensive nature of the involvement there were few clinical signs and symptoms reported by patients. 43.8 per cent of canines were lying palatal to the arch, 18.7 per cent were in the line of the arch and 37.5 per cent were buccal. Significantly 15.6 per cent were buccal and erupted. The path of canine eruption was mesio-horizontal in 21 cases. No relationship could be found between resorption and the retention or loss of the deciduous canine. The canine root formation was virtually complete in 31 of the involved canines. The study indicated that the problem is often diagnosed late both in relation to the patient's age and the extent of resorption present. It is suggested that the problem may be underestimated by dental practitioners.
The aim of this study was to evaluate the risk of root resorption during orthodontic treatment of patients with aplasia, and to analyse the relative importance of some anamnestic and treatment variables. The subjects comprised 68 orthodontically treated patients with 1-16 congenitally missing teeth. The age of the patients was 11-20 years (mean 15 years). All patients were treated with fixed edgewise appliances. The purpose of the orthodontic treatment varied: to create optimal conditions for prosthetic restorations or osseointegrated implants, or to achieve aesthetic and functional alignment of teeth in less severe cases. The degree of root resorption was assessed before and after treatment from intra-oral radiographs of the maxillary incisors using a scale of 0-4. In all, 186 maxillary incisors were evaluated. The degree of apical root resorption was significantly greater in cases of multiple aplasia (4-16 missing teeth) than in those with only one to three missing teeth. Root form, treatment time with rectangular wires and intermaxillary elastics, and total treatment time were significantly related to root resorption. Discriminant analysis disclosed that the following variables were the most important determinants of root resorption: number of missing teeth, root form, and time with rectangular archwires and intermaxillary elastics. It is concluded that there is a high risk of apical root resorption during orthodontic treatment in patients with multiple aplasia (four or more teeth), in particular in teeth with an abnormal root form and lengthy treatment with elastics and rectangular archwires.
The purpose of the study was to analyse the mobility of teeth with severe orthodontically induced root resorption, at follow-up several years after active treatment, and to evaluate mobility in relation to root length and alveolar bone support. Seventy-three maxillary incisors were examined in 20 patients, 10-15 years after active treatment in 13 patients (age 24-32 years) and 5-10 years after active treatment in seven patients (age 20-25 years). All had worn fixed or removable retainers; seven still had bonded twistflex retainers. Total root length and intra-alveolar root length were measured on intra-oral radiographs. Tooth mobility was assessed clinically according to Miller's Index (0-4) and the Periotest method. Crestal alveolar bone level, periodontal pocket depth, gingival, and plaque indices, occlusal contacts during occlusion and function, and dental wear were recorded. There was a significant correlation (P < 0.05) between tooth mobility, and total root length and intra-alveolar root length. No correlation was found between tooth mobility and retention with twistflex retainers. None of the variables for assessment of periodontal status, occlusion and function were related to total root length or tooth mobility. It is concluded that there is a risk of tooth mobility in a maxillary incisor that undergoes severe root resorption during orthodontic treatment, if the remaining total root length is < or = 9 mm. The risk is less if the remaining root length is > 9 mm. Follow-up of teeth with severe orthodontically induced root resorption is indicated.
Orthodontic treatment for patients with uni- or bilateral congenitally missing lateral incisors is a challenge to effective treatment planning. The two major alternatives, orthodontic space closure or space opening for prosthetic replacements, can both compromise aesthetics, periodontal health, and function. The aim of this retrospective study was to examine treated patients who had congenitally missing lateral incisors and to compare their opinion of the aesthetic result with the dentists' opinions of occlusal function and periodontal health. In this sample, 50 patients were identified. Thirty had been treated with orthodontic space closure, and 20 by space opening and a prosthesis (porcelain bonded to gold and resin bonded bridges). The patient's opinion of the aesthetic result was evaluated using the Eastman Esthetic Index questionnaire and during a structured interview. The functional status, dental contact patterns, periodontal condition, and quality of the prosthetic replacement was evaluated. In general, subjects treated with orthodontic space closure were more satisfied with the appearance of their teeth than those who had a prosthesis. No significant differences in the prevalence of signs and symptoms of temporomandibular dysfunction (TMD) were found. However, patients with prosthetic replacements had impaired periodontal health with accumulation of plaque and gingivitis. The conclusion of this study is that orthodontic space closure produces results that are well accepted by patients, does not impair temporomandibular joint (TMJ) function, and encourages periodontal health in comparison with prosthetic replacements.
Computed tomography of the maxillary alveolar arch was performed in three children with delayed eruption of one or both maxillary cuspids. Computed tomography demonstrated close contact between the ectopically localized and nonerupted canine and the lateral incisor. The lesion was unilateral in two patients and bilateral in one. In two patients resorption of the lateral incisor root was demonstrated. Moreover, CT permitted exact determination of the extent of the lesion by differentiating between superficial cementodentine resorption limited to the cementodentine (superficial resorption) and resorption extending into the pulpal canal (pulpal canal involvement).
A case of a compound odontoma caused delayed eruption of a central incisor in the maxilla is presented with clinical, radiographic, and microscopic findings. The odontoma was surgically removed and microscopic examination showed a lot of crown-like structures in a very irregular form, some of which were fused to each other at their apical parts. Enamel and pre-enamel were totally abnormal, whereas the inside of the pulp chamber tissue did not present any histological sign of functional tissue. The most homogeneous tissue was dentin. The removal of the odontoma was followed by a rapid eruption of the impacted central incisor.
The purpose of this study was to evaluate the use of fiber-composite laminate, a reinforcement ribbon embedded throughout a composite restoration, to reinforce immature maxillary central incisors. Twenty-six mature maxillary central incisors were prepared a minimum of 3 mm below the facial cementoenamel junction to simulate immature nonvital teeth. They were separated into 3 groups: group 1 was unfilled and served as a control; group 2 was filled to the depth of the preparation with composite; and group 3 was filled with composite and Connect Reinforcement Ribbon. The specimens were subjected to class I loading in an Instron Testing Machine until catastrophic failure occurred. The results indicate a highly significant difference between the groups (p < or = 0.003). Group 1 fractured at an average load of 31.08 kg, group 2 at 51.00 kg, and group 3 at 37.93 kg. These findings suggest that composite alone increases fracture resistance of the immature tooth model more than composite with Reinforcement Ribbon.